A job to do when it's dusty out? (4)
I believe the answer is:
duty
'a job' is the definition.
(thesaurus)
'do when it's dusty out?' is the wordplay.
I cannot really understand how this works, but
'do' could be 'ut' (synonyms) and 'ut' is found within the answer.
This explanation may well be incorrect...
'to' acts as a link.
Can you help me to learn more?
(Other definitions for duty that I've seen before include "Not subject to customs tax" , "Service - tax - office" , "assignment" , "Is one bound" , "Task; military service" .)